Revision as of 17:51, 24 January 2011

Objective

This tech note outlines the main differences in advanced Border Gateway Protocol (BGP) support between Cisco® NX-OS Software and Cisco IOS® Software. Sample configurations are included for Cisco NX-OS and Cisco IOS Software for some common features to demonstrate the similarities and differences. Please refer to the NX-OS documentation on Cisco.com for a complete list of supported features.

Multiple policy templates can be assigned per neighbor. Policy templates are executed in order based on the configured sequence number.

Policy templates are inherited by a neighbor through the neighbor and address-family configuration mode.

Route-map polices can configure BGP attributes such as as-path, community lists, community attributes, dampening, local preference, metric type, origin, and weight.

Route-map polices can be applied per neighbor for inbound and outbound routing policies.

Configuration Comparison

The following sample code shows the configuration similarities and differences between the Cisco NX-OS and Cisco IOS Software CLIs. The configurations are very similar with the exception of the hierarchy used in Cisco NX-OS.

Cisco IOS CLI

Cisco NX-OS CLI

Configuring a Route-Reflector

router bgp 10

no synchronization

network 192.168.11.1 mask 255.255.255.255

neighbor 192.168.2.1 remote-as 10

neighbor 192.168.2.1 update-source Loopback0

neighbor 192.168.2.1 route-reflector-client

no auto-summary

router bgp 10

address-family ipv4 unicast

network 192.168.11.1/32

neighbor 192.168.2.1 remote-as 10

update-source loopback0

address-family ipv4 unicast

route-reflector-client

Configuring Confederations

router bgp

no synchronization

bgp confederation identifier 10

bgp confederation peers 65535

network 192.168.11.1 mask 255.255.255.255

neighbor 192.168.10.2 remote-as 65535

no auto-summary

router bgp 65534

confederation identifier 10

confederation peers 65535

address-family ipv4 unicast

network 192.168.11.1/32

neighbor 192.168.10.2 remote-as 65535

address-family ipv4 unicast

Configuring a Peer Template

router bgp 10

no synchronization

network 192.168.11.1 mask 255.255.255.255

neighbor IBGP-Template peer-group

neighbor IBGP-Template password cisco123

neighbor IBGP-Template update-source Loopback0

neighbor 192.168.2.1 remote-as 10

neighbor 192.168.2.1 peer-group IBGP-Template

no auto-summary

router bgp 10

address-family ipv4 unicast

network 192.168.11.1/32

template peer IBGP-Template

password 3 a667d47acc18ea6b

update-source loopback0

address-family ipv4 unicast

neighbor 192.168.2.1 remote-as 10

inherit peer IBGP-Template

Configuring a Policy Template

router bgp 10

template peer-policy EBGP-Policy

default-originate

send-community

exit-peer-policy

no synchronization

network 192.168.11.1 mask 255.255.255.255

neighbor 192.168.10.2 remote-as 20

neighbor 192.168.10.2 inherit peer-policy EBGP-Policy

no auto-summary

router bgp 10

address-family ipv4 unicast

network 192.168.11.1/32

template peer-policy EBGP-Policy

send-community

default-originate

neighbor 192.168.10.2 remote-as 20

address-family ipv4 unicast

inherit peer-policy EBGP-Policy 10

Configuring an Outbound Neighbor Route-Map Policy

route-map EBGP-Policy permit 10

set as-path prepend 10 10 10

router bgp 10

no synchronization

network 192.168.11.1 mask 255.255.255.255

neighbor 192.168.10.2 remote-as 20

neighbor 192.168.10.2 route-map EBGP-Policy out

no auto-summary

route-map EBGP-Policy permit 10

set as-path prepend 10 10 10

router bgp 10

address-family ipv4 unicast

network 192.168.11.1/32

neighbor 192.168.10.2 remote-as 20

address-family ipv4 unicast

route-map EBGP-Policy out

Configuring an Outbound Prefix-List

ip prefix-list EBGP-Policy seq 5 permit 192.168.11.1/32

router bgp 10

no synchronization

neighbor 192.168.10.2 remote-as 20

neighbor 192.168.10.2 prefix-list EBGP-Policy out

no auto-summary

ip prefix-list EBGP-Policy seq 5 permit 192.168.11.1/32

router bgp 10

neighbor 192.168.10.2 remote-as 20

address-family ipv4 unicast

prefix-list EBGP-Policy out

Verification Command Comparison

The following table compares some useful show commands for verifying and troubleshooting a BGP network configuration.

Cisco NX-OS BGP

Cisco IOS Software BGP

Command Description

show bgp convergence

-

Displays global convergence information

show bgp process

-

Displays global BGP process information

show bgp sessions

-

Displays information for all neighbors

show bgp statistics

-

Displays global BGP process statistics

-

-

-

show ip bgp<option>

show ip bgp

Displays BGP Process and BGP table entries

show ip bgpx.x.x.x

show ip bgp x.x.x.x

Displays a specific network in the BGP table

show ip bgpx.x.x.xvrf

-

Displays a network in a specified VRF BGP table

show ip bgpx.x.x.x/len

show ip bgp x.x.x.xmask

Displays a specific prefix in the BGP table

show ip bgpx.x.x.x/lenlonger-prefix

show ip bgp x.x.x.x mask longer-prefix

Displays a prefix in the table with longer prefixes

show ip bgp all

show ip bgp all

Displays the BGP table for all protocol families

show ip bgp community<word>

show ip bgp community <#>

Displays routes with a specific regular expression

show ip bgp community <aa:nn>

-

Displays routes with a specific community value

show ip bgp community internet

-

Displays BGP routes advertised to the Internet

show ip bgp community no-advertise

show ip bgp community no-advertise

Displays BGP routes not advertised to peers

show ip bgp community no-export

show ip bgp community no-export

Displays BGP routes not exported to next AS

show ip bgp community no-export-spoofed

-

Displays BGP routes not sent to outside local AS

show ip bgp community-list<name>

show ip bgp community-list <name>

Displays a specific BGP community list

show ip bgp dampening dampened-paths

show ip bgp dampening dampened-paths

Displays all Dampened paths

show ip bgp dampening flap-statistics

show ip bgp dampening flap-statistics

Displays flap statistics for BGP routes

show ip bgp dampening history-paths

-

Displays all history paths

show ip bgp dampening parameters

show ip bgp dampening parameters

Displays all of the Dampening parameters

show ip bgp extcommunity<word>

-

Displays routes with a specific regular expression for extended communities